1. Field of the Invention
Embodiments of the present invention relate to methods and apparatuses for dressing and treating a wound with topical negative pressure (TNP) therapy. In particular, but not exclusively, embodiments disclosed herein relate to a wound dressing for providing protection to a wound site, in which the wound dressing acts as a buffer to help prevent compression or shear forces exerted on the wound dressing, for example due to patient movement, from harming a healing wound. Embodiments of the wound dressing may act as a waste canister to collect and store wound exudate removed from a wound site, and also relate to the management of solid build-up in a wound dressing covering a wound site whilst TNP therapy is applied. Further, embodiments disclosed herein relate to a method and suction port for applying negative pressure to a wound dressing and a method of manufacturing a suction port and wound dressing.
2. Description of the Related Art
Many different types of wound dressing are known for aiding in the healing process of a human or animal. These different types of wound dressing include many different types of materials and layers, for example, gauze, pads, foam pads or multi-layer wound dressings.
In addition, TNP therapy, sometimes referred as vacuum assisted closure or negative pressure wound therapy, has recently been proposed as a successful mechanism for improving the healing rate of a wound. Such therapy is applicable to a broad range of wounds such as incisional wounds, open wounds and abdominal wounds or the like.
TNP therapy assists in the closure and healing of wounds by reducing tissue oedema; encouraging blood flow; stimulating the formation of granulation tissue; removing excess exudates and may reduce bacterial load and thus, infection to the wound. Furthermore, TNP therapy permits less outside disturbance of the wound and promotes more rapid healing.
During TNP therapy, a suction source such as a vacuum pump or the like is utilized to create a negative pressure region. That is to say, a region where an experienced pressure is below that of the surroundings. Wound exudate and other potentially harmful material is extracted from the wound region and must be stored for later disposal. A problem associated with many known techniques is that a separate canister must be provided for storage of such exudate. Provision of such canisters is costly and bulky and prone to failure.
A proposal has been suggested to store extracted wound exudate in the wound dressing itself that is used to cover a wound site and create the wound chamber region where negative pressure is established. However, it is known that many different wound types can exude high flow rates of exudate and therefore storage of exuding material in a wound dressing can be problematical since the wound dressing will only have a limited capacity for fluid uptake before a dressing change is required. This can limit a time of use between dressing changes and can prove costly if many wound dressings are required to treat a given wound.
It has been suggested as a solution to this problem, that a liquid impermeable moisture vapor permeable cover layer can be utilized as an uppermost cover layer for the wound dressing. The air impermeable nature of the cover layer provides a sealing layer over the wound site so that negative pressure can be established below the dressing in the region of the wound. The moisture vapor permeability of this covering layer is selected so that liquid can constantly evaporate away from the top of the dressing. This means that as therapy is continued the dressing does not have to take up and hold all liquid exuding from the wound. Rather, some liquid is constantly escaping in the form of moisture vapor from the upper environs of the dressing.
Whilst such dressings work well in practice, the continuous evaporation of moisture vapor from the dressing can lead to the problem of crust formation in the dressing. That is to say, because of the continuous drawing of liquid away from the wound site solid particulate matter is more prone to formation and accumulation in the dressing. Under certain circumstances the build-up of such solid material can lead to blockages forming in the wound dressing in the flowpath between the wound and the source of negative pressure. This can potentially cause problems in that therapy may need to be halted to change a dressing if the blockages reach a critical level.
Further, there is much prior art available relating to the provision of apparatuses and methods of use thereof for the application of TNP therapy to wounds together with other therapeutic processes intended to enhance the effects of the TNP therapy.
It will be appreciated that from time to time accidents may happen to patients undergoing negative pressure wound therapy. Such accidents might cause short term or long term forces to be applied to a dressing covering a wound. Alternatively patient movement may bring the patient and any dressing covering a healing wound into contact with an external object. In such occurrences compressive forces or lateral forces may occur. Such force can cause disturbance of a wound bed which can damage a wound site. A particular cause for concern is during the treatment of skin graft wounds. Under such conditions lateral forces can entirely upset or tear apart a healing skin graft region.